This invention relates generally to an end cap for a paint roller frame, and in particular, to an improved end cap for a paint roller frame that extends the useful life of the paint roller frame.
Paint roller frames typically include a handle having a hand grip, a shaft extending at a right angle to the handle, and a roller cage assembly mounted on the shaft. The roller cage assembly includes inboard and outboard end caps and supports a roller cover by frictional retention.
U.S. Pat. No. 4,332,067 discloses a paint roller frame of the general type discussed above. The '067 patent shows a plurality of cross wires brazed at their ends to wire rings. Roller end caps are then forced over the wire rings.
The cross wires collectively define an outer diameter that is slightly greater than the inside diameter of the roller cover. When the cover is forced over the cross wires, they are resiliently flexed inwardly, thereby creating an outward biasing force on the cover. This force tends to frictionally maintain the cover firmly in place. The described design suffers from the potential problem of one or more of the cross wires breaking from the wire rings at the brazed connection. When this happens, the cross wires become loose and fail to provide support and fixed positioning for the roller cover. As a result, the roller cover, when pressed against a surface, can deform inwardly in that area and fail to effectively coat the surface. Also, the roller cover is more susceptible to movement axially on the roller cage and a possible failure to rotate in unison with the roller cage. These problems can so impair the functioning of the paint roller frame as to render it useless.
U.S. Pat. No. 4,897,893 also discloses a paint roller frame of the general type discussed above. Rather than attaching the cross wires of the '893 patent to a wire ring, they are individually secured in an annular slot or groove in the end cap. This construction obviously eliminates the problem of the cross wires breaking from the wire ring. However, by eliminating the wire ring, the advantages of the wire ring structure are also eliminated and new problems created. For example, there is missing the support for the roller cover that is provided by a rigid wire ring in each end cap. The only support for the roller cover at its ends are the end caps themselves, which are made of plastic and do not provide the durability or strength of a metal support. Furthermore, the connection between the ends of the cross wires and the end cap is ineffective. Because the ends of the wires are simply stuck in an annular groove, the wires are subject to circumferential movement around the groove and axial movement in and out of the groove. The lack of a unitary bond between all the cross wires at their ends causes a nonuniform resilience of the roller cage as a whole, which can result in an uneven and irregular coating of surfaces. Moreover, there is little to prevent an end cap from axially separating from the ends of the cross wires.
In addition, the outboard end cap of the '893 patent is a two piece structure in which each piece must be molded to close tolerances in order to function effectively. This increases the cost of manufacture.